New LiMnPO4 Developed as Cathode Material for Li-ion Batteries

Mar 19, 2010 18:29 Kouji Kariatsumari, Nikkei Electronics

Sumitomo Osaka Cement Co Ltd announced March 18, 2010, that it has developed lithium manganese phosphate (LiMnPO₄) for use as a positive-electrode material for lithium-ion (Li-ion) rechargeable batteries.

It has not been evaluated as a battery cell yet, but it has as high an electric potential as 4.1V against metal lithium and a capacity of more than 162mAh/g. The company plans to start sample shipment within three months.

A material with a high thermal stability has been required for middle- and large-size Li-ion batteries used in electric vehicles, etc. Sumitomo Osaka Cement has already commercialized lithium iron phosphate (LiFePO₄) with a high thermal stability, but its electric potential against metal lithium is as low as 3.4V.

LiMnPO₄ has been drawing attention as the next-generation positive-electrode material because its electric potential is 0.7V higher than that of LiFePO₄. However, because the electrical conductivity of the LiMnPO₄ is less than 1/1,000 that of LiFePO₄, it cannot be easily used for high-output devices.

This time, Sumitomo Osaka Cement solved that problem by reducing the particle size to 20-30nm and developing a method to densely cover conducting substances such as carbon, it said.

The newly-developed LiMnPO₄ can be produced with the same synthesis method as used for LiFePO₄. So, the company can produce the LiMnPO₄ by using facilities similar to those used to produce LiFePO₄. It plans to commercialize the LiMnPO₄ until 2012.

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